<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <ul>
          <li>1</li>
          <li>2</li>
          <li>3</li>
          <li>4</li>
        </ul>
      </div>
</body>
<script src="../js/demo.js"></script>
</html>